Subcellular localization of melon (Cucumis melo L.) glutamine synthetases

Abstract

To physically characterize the subcellular localizations of M-GS1 (GenBank accession number: DQ851867) and M-GS2 (GenBank accession: AY773090), the first two glutamine synthetase (GS) genes isolated from melon, we constructed two recombinant plant expression vectors, in which the coding sequence of either M-GS1 or M-GS2 was fused with that of the yellow fluorescence protein YFP, using CamV 35S as the promoter. The recombinant plant expression vectors were then transformed into the onion epidermal cells via gene gun bombardments. After transient expression, fluorescence emission from the expressed products in cells was visualized and analyzed using laser-scanning confocal microscope techniques. The results indicated that M-GS2 was localized in the chloroplast while M-GS1 in the cytosol. It is the first report to precisely characterize the subcellular localization of melon GS, which added to the foundation for further analyses on the roles of melon GS genes in enhancing plant N use efficiency. © 2012 Springer-Verlag GmbH.